Joel_BC
Super Self-Sufficient
I have a garden tractor (doubles as a ride-it lawnmower) that wouldn't start yesterday. Turned the starter key and it was backfiring, not kicking over. Strange, because I'd used it maybe four days before and it was starting okay and seemed to be running normally.
The first thing I did was remove the spark plug. It was badly oil fouled. So I cleaned it. Put it back in, and the engine started right up!
The oil had been igniting, but in the wrong phase of the engines 4-part sequence (this is a 4-ycle engine). The engine had been igniting and exploding the gasoline properly, but obviously also igniting the oil on the intake phase. That meant the engine was working against itself.
In a situation like this, you could replace the plug with a new one, or clean the existing one. I used some penetrating oil to thin the motor oil on/in the plug, and then sandblasted the inside of the plug - then cleaned any remaining sand out of the plug using compressed air (because I happen to have this equipment). The plug was clean and dry when I put it back in the engine.
By the way, I drained the old oil, which was 5-30w and replaced it with straight 30w oil, as the tractor and its engine are over 20 years old and there's certainly the usual wear on the oil rings and valve guides. I'm expecting this will reduce the oil fouling of the spark plug.
With backfiring in any 4-cycle engine (lawnmower, pump, generator, etc), first place to check is the spark plug.
The first thing I did was remove the spark plug. It was badly oil fouled. So I cleaned it. Put it back in, and the engine started right up!
The oil had been igniting, but in the wrong phase of the engines 4-part sequence (this is a 4-ycle engine). The engine had been igniting and exploding the gasoline properly, but obviously also igniting the oil on the intake phase. That meant the engine was working against itself.
In a situation like this, you could replace the plug with a new one, or clean the existing one. I used some penetrating oil to thin the motor oil on/in the plug, and then sandblasted the inside of the plug - then cleaned any remaining sand out of the plug using compressed air (because I happen to have this equipment). The plug was clean and dry when I put it back in the engine.
By the way, I drained the old oil, which was 5-30w and replaced it with straight 30w oil, as the tractor and its engine are over 20 years old and there's certainly the usual wear on the oil rings and valve guides. I'm expecting this will reduce the oil fouling of the spark plug.
With backfiring in any 4-cycle engine (lawnmower, pump, generator, etc), first place to check is the spark plug.
